Old 11-16-2010, 11:32 PM #1
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Default 5k ohm pot for driver

hey my driver recently crapped out and i am building my own, ther parts i have so far are lm317, 1n4001 diodes, 47 uf 35v capactitor,


what i need it a pot but i looked around my house and found a 5k ohm pot. will this work? ill be using for a red laser. also what plans did you guys go off of? thx


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Old 11-16-2010, 11:59 PM #2
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Default Re: 5k ohm pot for driver

Well you would be better off not even using one if its gonna be a 5k ohm theres a good one at radioshack for like $7 Its 25 ohm
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Old 11-17-2010, 12:19 AM #3
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Default Re: 5k ohm pot for driver

will it do anything?
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Old 11-17-2010, 12:26 AM #4
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Default Re: 5k ohm pot for driver

5KOhm is not a good idea for a driver.

The resistor in the driver have to carry the full current and produce a voltage drop of 1.25V.
Depending on the diode you are using that would be a resistance of 1.25Ohm (1A) and up (less amps), you cannot get that reliably from a 5Kohm pot.

Go buy a smaller one or some resistors, remember that they will also have to be able to carry the effect of the current times the 1.25V.

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will it do anything?
Yes it will.
When you are fiddling at the low end between 100Ohm an 0Ohm you will accidentally turn it to 0ohm and burn off your diode.
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Old 11-17-2010, 02:39 PM #5
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Default Re: 5k ohm pot for driver

^And for that reason, the recommendation is to have series resistance equal to the value that will limit to a max current.

Unless it's a 15-turn pot, it will not be very helpful for you.
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